1. Field of the Invention
The present invention relates to a method and system for performing Peer-To-Peer (P2P) communications in a communication system. More particularly, the present invention relates to a method and system for performing P2P communications in a cellular communication system.
2. Description of the Related Art
In a communication system, there are, by and large, two communication modes for communications between a transmitting MS, i.e. a source MS (MS_S) and a receiving MS, i.e. a destination MS (MS_D). The two communication modes are a cellular communication mode and a P2P communication mode. In the cellular communication mode, MS_S communicates with MS_D via a Base Station (BS), whereas in the P2P communication mode, MS_S communicates directly with MS_D without the aid of the BS.
A cellular-mode MS establishes a P2P connection to operate in the P2P communication mode. With reference to FIG. 1, a conventional operation for establishing the P2P connection by the cellular-mode MS will be described in the context of Bluetooth communications as an example. In FIG. 1, MS_S requesting P2P connection setup is referred to as a first device and MS_D to which a P2P connection is to be established with is referred to as a second device. The first and second devices exchange signals via a radio interface.
FIG. 1 illustrates a conventional operation for establishing a P2P connection using Bluetooth by a cellular-mode MS.
Referring to FIG. 1, a first device 101 transmits its 48-bit unique Bluetooth Device ADDRess (BD_ADDR) 113 to a second device 103 via wireless interface 105. A random number generator 107 of the second device 103 generates a 128-bit Authentication RANDom number (AU_RAND) 115 and transmits it to the first device 101 via wireless interface 105.
The first and second devices 101 and 103 generate authentication response strings (SRESs) using the BD_ADDR 113, the AU_RAND 115, and link keys 117 and 119 according to their encryption algorithms 109 and 111. The link keys 117 and 119 include information generated using a PIN number shared between the first and second devices 101 and 103. That is, the encryption algorithm 109 of the first device 101 generates a first authentication response string (SRES1) using the BD_ADDR 113, the received AU_RAND 115, and the link key 117 of the first device 101, and the encryption algorithm 111 of the second device 103 generates a second authentication response string (SRES2) using the received BD_ADDR 113, the AU_RAND 115, and the link key 119 of the second device 103.
A comparator of the second device 103 compares SRES1 and SRES2 in step 121. If SRES1 and SRES2 are identical, a P2P connection is established in step 123. If SRES1 and SRES2 are different, the P2P connection setup procedure is terminated in step 125.
For P2P communications, MS_D operates in a reception waiting mode in order to receive a P2P connection setup request. The reception waiting mode refers to a mode in which MS_D keeps its reception sensor activated to receive the P2P connection setup request, thus unnecessarily consuming power.
In addition, the P2P communications require a preliminary agreement between MS_S and MS_D. To make the agreement, MS_S transmits its unique Media Access Control (MAC) address, for example, BD_ADDR to MS_D so that MS_D can identify MS_S. During the transmission, the unique identification information of MS_S is exposed to neighbor BSs, thereby risking the security of the unique identification information.